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Sticky Prices or Sticky Wages? An Equivalence Result

Florin Bilbiie, Mathias Trabandt
Review of Economics and Statistics, forthcoming
Abstract

We show an equivalence result in the standard representative agent New Keynesian model after demand, wage markup and correlated price markup and TFP shocks: assuming sticky prices and flexible wages yields identical allocations for GDP, consumption, labor, inflation and interest rates to the opposite case- flexible prices and sticky wages. This equivalence result arises if the price and wage Phillips curves' slopes are identical and generalizes to any pair of price and wage Phillips curve slopes such that their sum and product are identical. Nevertheless, the cyclical implications for profits and wages are substantially different. We discuss how the equivalence breaks when these factor-distributional implications matter for aggregate allocations, e.g. in New Keynesian models with heterogeneous agents, endogenous firm entry, and non-constant returns to scale in production. Lastly, we point to an econometric identification problem raised by our equivalence result and discuss possible solutions thereof.

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Expectations, Infections, and Economic Activity

Martin S. Eichenbaum, Miguel Godinho de Matos, Francisco Lima, Sergio Rebelo, Mathias Trabandt
Journal of Political Economy, No. 8, 2024
Abstract
The Covid epidemic had a large impact on economic activity. In contrast, the dramatic decline in mortality from infectious diseases over the past 120 years had a small economic impact. We argue that people's response to successive Covid waves helps reconcile these two findings. Our analysis uses a unique administrative data set with anonymized monthly expenditures at the individual level that covers the first three Covid waves. Consumer expenditures fell by about the same amount in the first and third waves, even though the risk of getting infected was larger in the third wave. We find that people had pessimistic prior beliefs about the case-fatality rates that converged over time to the true case-fatality rates. Using a model where Covid is endemic, we show that the impact of Covid is small when people know the true case-fatality rate but large when people have empirically-plausible pessimistic prior beliefs about the case-fatality rate. These results reconcile the large economic impact of Covid with the small effect of the secular decline in mortality from infectious diseases estimated in the literature.
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Understanding Post-Covid Inflation Dynamics

Martín Harding, Jesper Lindé, Mathias Trabandt
Journal of Monetary Economics, November 2023
Abstract
We propose a macroeconomic model with a nonlinear Phillips curve that has a flat slope when inflationary pressures are subdued and steepens when inflationary pressures are elevated. The nonlinear Phillips curve in our model arises due to a quasi-kinked demand schedule for goods produced by firms. Our model can jointly account for the modest decline in inflation during the Great Recession and the surge in inflation during the post-COVID period. Because our model implies a stronger transmission of shocks when inflation is high, it generates conditional heteroskedasticity in inflation and inflation risk. Hence, our model can generate more sizeable inflation surges due to cost-push and demand shocks than a standard linearized model. Finally, our model implies that the central bank faces a more severe trade-off between inflation and output stabilization when inflation is elevated.
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Comment on “Optimal monetary policy in an estimated SIR model by G. Benmir, I. Jaccard, and G. Vermandel”

Mathias Trabandt
European Economic Review, September 2023
Abstract

Benmir, Jaccard, and Vermandel (2023, BJV) seek to answer the following set of topical and important research questions: (i) How should monetary policy be conducted during a pandemic?, (ii) How do health considerations affect the conduct of monetary policy?, and (iii) How does the presence of contagion risk affect the main building blocks of the New Keynesian model?

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Epidemics in the New Keynesian Model

Martin S. Eichenbaum, Sergio Rebelo, Mathias Trabandt
Journal of Economic Dynamics and Control, July 2022
Abstract
This paper documents the behavior of key macro aggregates in the wake of the Covid epidemic. We show that a unique feature of the Covid recession is that the peak-to-trough decline is roughly the same for consumption, investment, and output. In contrast to the 2008 recession, there was only a short-lived rise in financial stress that quickly subsided. Finally, there was mild deflation between the peak and the trough of the Covid recession. We argue that a New Keynesian model that explicitly incorporates epidemic dynamics captures these qualitative features of the Covid recession. A key feature of the model is that Covid acts like a negative shock to the demand for consumption and the supply of labor.
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The Macroeconomics of Testing and Quarantining

Martin S. Eichenbaum, Sergio Rebelo, Mathias Trabandt
Journal of Economic Dynamics and Control, May 2022
Abstract
We develop a SIR-based macroeconomic model to study the impact of testing/ quarantining and social distancing/mask use on health and economic outcomes. These policies can dramatically reduce the costs of an epidemic. Absent testing/quarantining, the main effect of social distancing and mask use on health outcomes is to delay, rather than reduce, epidemic-related deaths. Social distancing and mask use reduce the severity of the epidemic-related recession but prolong its duration. There is an important synergy between social distancing and mask use and testing/quarantining. Social distancing and mask use buy time for testing and quarantining to come to the rescue. The benefits of testing/quarantining are even larger when people can get reinfected, either because the virus mutates or immunity is temporary.
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Inequality in Life and Death

Martin S. Eichenbaum, Sergio Rebelo, Mathias Trabandt
IMF Economic Review, March 2022
Abstract
We argue that the COVID epidemic disproportionately affected the economic well-being and health of poor people. To disentangle the forces that generated this outcome, we construct a model that is consistent with the heterogeneous impact of the COVID recession on low- and high-income people. According to our model, two-thirds of the inequality in COVID deaths reflect preexisting inequality in comorbidity rates and access to quality health care. The remaining third stems from the fact that low-income people work in occupations where the risk of infection is high. Our model also implies that the rise in income inequality generated by the COVID epidemic reflects the nature of the goods that low-income people produce. Finally, we assess the health-income trade-offs associated with fiscal transfers to the poor and mandatory containment policies.
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Resolving the Missing Deflation Puzzle

Martín Harding, Jesper Lindé, Mathias Trabandt
Journal of Monetary Economics, March 2022
Abstract
A resolution of the missing deflation puzzle is proposed. Our resolution stresses the importance of nonlinearities in price- and wage-setting when the economy is exposed to large shocks. We show that a nonlinear macroeconomic model with real rigidities resolves the missing deflation puzzle, while a linearized version of the same underlying nonlinear model fails to do so. In addition, our nonlinear model reproduces the skewness of inflation and other macroeconomic variables observed in post-war U.S. data. All told, our results caution against the common practice of using linearized models to study inflation and output dynamics.
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The Macroeconomics of Epidemics

Martin S. Eichenbaum, Sergio Rebelo, Mathias Trabandt
Review of Financial Studies, No. 11, 2021
Abstract
We extend the canonical epidemiology model to study the interaction between economic decisions and epidemics. Our model implies that people cut back on consumption and work to reduce the chances of being infected. These decisions reduce the severity of the epidemic but exacerbate the size of the associated recession. The competitive equilibrium is not socially optimal because infected people do not fully internalize the effect of their economic decisions on the spread of the virus. In our benchmark model, the best simple containment policy increases the severity of the recession but saves roughly half a million lives in the United States.
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Why is Unemployment so Countercyclical?

Lawrence J. Christiano, Martin S. Eichenbaum, Mathias Trabandt
Review of Economic Dynamics, July 2021
Abstract
We argue that wage inertia plays a pivotal role in allowing empirically plausible variants of the standard search and matching model to account for the large countercyclical response of unemployment to shocks.
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